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Physical Chemistry

Physical Chemistry . Properties of Matter:.

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Physical Chemistry

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  1. Physical Chemistry

  2. Properties of Matter: • Atomsare the fundamental building block of matter. An apple is to earth as an atom is to an apple. Atoms are about 10 –10 m in size. There are 1023 atoms in a gram of water. Atoms cannot be seen with visible light, but instead with electron beams. (scanning tunneling microscopes.)

  3. Atomic Structure: An atom is mostly empty space. Almost all the mass is found in the nucleus. • The nucleus contains positively charged protons and neutrons (n0) which have no charge. • # of protons = atomic # • The number of n0 vary in the atom • Isotopes - Atoms with • the same number of p+, • but different number of n0 • # of n0= • atomic mass – atomic #

  4. Electrons: (e-) Negatively charged particles (1800 times less massive than protons) that spin around the nucleus of the atom. • Most atoms have exactly the same number of p+ as there are e- giving the atom no net charge. • ion – an electrical charged atom with either an excess or lack of e- compared to p+.

  5. How many neutrons, protons, and electrons do Zn+1 and Ga+3 have?

  6. Elements: Atoms of the same kind. They are all found on the periodic table in mass order. Living things are made of mostly oxygen (O), carbon (C), hydrogen (H), nitrogen (N), and Calcium (Ca). Elements are constantly being recycled. • Q1) What is the symbol for Iron? _______ Potassium ? ________ • Elements in the same group (column) have similar properties.

  7. Molecules: Atoms that join to become large particles. • Water is a molecule made of 1 _______________ and 2 ________________. • The molecules can join by sharing electrons covalent bond (CO2) or electrons can be transferred between atoms (NaCl).

  8. Phases of Matter: • Solids – molecules vibrating about a fixed position, • Liquid- molecules wander about the material, • gas – molecules move extremely quickly. If a substance is heated more it can go into the plasma phase. • Plasma is found in the sun and UV lights. Plasma consists of free electrons and positive ions.

  9. Density: How tightly the material is packed together. The amount of mass per unit volume. • Density uses the symbol  (looks like a p, but is actually the greek letter rho) • Density () = mass (m) / Volume (V) •  = m/V • Density varies from Osmium (22.6 g/cm3) to outer space (10-24 g/cm3) • Density varies with pressure and temperature. • Q1) What are the SI units for density? _________ What units are often used? _________________

  10. Specific Gravity: the ratio of the density of water at 4C to that of a substance. This gives you how much more dense it is. The nice thing is that since it is a ratio, units cancel out. • Q2) What is the density of water at 4 C? ________________________________ • Q3) What is the density of a solid with a volume of 25 cm3 and a mass of 49g? b) what is the specific gravity?

  11. Conversions of mass and volume: • Q4) Convert the following using these conversion factors: • 1 mL = 1 cm3 100 cm = 1m 1000 g = 1 kg 2.54 cm = 1 in 12 in = 1 ft 2.2 lb = 1 kg a) 46, 700 g into lbs b) 4.78 m3 into Liters

  12. Measuring Mass and Volume: • You can measure mass using a balance or a scale. • Volume is a little trickier. • For a cube you can measure the volume with V = lwh (length x width x height) • For a liquid you can measure the volume in a graduated cylinder. • For an irregular object you can measure the volume of water than put the object in and remeasure the volume of water. The difference is the mass of the object. • Q5) An irregular object has a mass of 175.5 g and is put into a beaker with originally 73.2 mL when the object is put in it raises up to 95.7 mL, What is the density of the object in g/cm3 and kg/m3? What is this substance?

  13. Board 1: A cube with a mass of 48g is made from a metal with a density of 6.5 g/cm3. What is the volume of the cube and the length of each edge? • Board 2: An irregular object is put in 72.9 mL of water and it raises up to 86.7 mL when the object is put in. The mass is measured and found to be 262.2 g. a) What is the density in g/cm3 b) And in kg/m3 c) what is its specific gravity d) what is this substance? • Boards 3: Convert the following: 324 cm3 into ft3

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